The purpose of this investigation is to analyse microscopic wear mechanism of ceramic coatings, based on friction tests in the CCD microscope. Following results were obtained ;(1) Microscopic wear modes of ceramic coatings can be classified into following three modes ;1) spalling of coating film at initial sliding passage2) spalling of coating film after certain sliding passages3) wear of coating film(2) Wear modes of coating film can be classified into following two modes ;1) flake formation : This is the severest wear mode of ceramics by macroscopic surface crack propagation.2) powder formation : This is caused by microscopic surface crack propagation.